docs: def revoke_permissions(self, ctype):
          """
          Remove all permissions for the content type to be removed
          """
          ContentType = apps.get_model('contenttypes', 'ContentType')
          try:
              Permission = apps.get_model('auth', 'Permission')
          except LookupError:
              return
  
          codenames = ['{0}_{1}'.format(perm, ctype) for perm in self.default_permissions]
          cascade_element = apps.get_model(self.label, 'cascadeelement')
          element_ctype = ContentType.objects.get_for_model(cascade_element)
          Permission.objects.filter(content_type=element_ctype, codename__in=codenames).delete()